It's there highest paved mountain pass in WA and may have been the highest pavement overall at some point. Sunrise, on Rainier, is paved to 6,400'.

Sherman Pass is lovely, and the entire ride from Republic is very scenic. There are some broad views in both directions. But if you're uncomfortable riding in traffic, this might be a pucker fest. Logging trucks can be scary. 😳 This might be one for a weekend?